No picture,Back light comes on then turns off

I have a Sony XBR-55x800H and It will power on and you see the back light come on then the white led on the front goes out. No other flashing lights. I took the back off and unplugged the left and right t-con connectors one at a time and the 2 sides come on and display only lines with no colors. Not sure what else to check. I do have test equipment just dont know where to start.